Resonant torsion oscillators are known, but are not typically employed in devices utilizing optical systems such as laser printing devices. Typically in laser printing devices, a scanning polygonal mirror is used for the purpose of scanning a light beam across a latent image storage device such as a photoconductor. A polygonal mirror scanning device requires relatively expensive air or other fluid bearings to ensure reliable performance of the scanning device as the rotational speed of the polygonal mirror increases to achieve higher print speeds. (Generally, print speed is measured in pages per minute (PPM)). Additionally, as rotational speed of the polygonal mirror increases, acoustic noise generated by the scanning device becomes a problem and contamination forms more readily on the rotating polygonal mirror. Also, power consumption increases proportionally with the square of the rotational speed of the polygonal mirror.
Despite these problems, high precision scanning devices employing mirrors remain dominant in the field primarily because of problems with other technologies. In the case of scanning devices using galvanometric oscillators, the problems include relatively low scan efficiency, relatively high laser modulation frequencies, scan speed instability, scan amplitude instability, and resonant frequency instability associated with environment.